Reversing-valve stem



(Model.)

S. L HAWKS Reversing T/'alVeVSijAalILv No. 241,654. 'Patented may 11,1581.

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SAMUEL L. HAVKS, OF BLOOMINGTON, ILLINOIS.

REvERsINc-VALVE STEM.

SPECIFICATION forming part of Letters Patent No. 241,654, dated May 1'7, 1881.

Application ledMarchQSl, 188]. (Model.)

To all whom it may concern Be it known that I, SAMUEL L. Hawks, of the city of Bloomington, in the county of Mc- Lean and State of Illinois, have invented certain Improvements in Valve-Stems, ot" which the following is a specication.

My improvement relates specially to the reversingvalve stems, (sometimes called the friction-stemsf) which are inserted in and operated by the hollow steam-pistons of the enn gines and pumps ofpower-brakes; and it consists in providing a spring friction-bearin g for the upper end or head of such stems in the or, on the other handyto cause a` leakage of steam at a point to obstruct the engineers view of the track, both of which difficulties, among others, my improvement avoids.

In the drawings, Figure l shows an engine andpump used in the operationof train-brakes with my improved stem A in place, the stem being operated by the striking of the piston D upon the lugs or flan ges B C alternately as it travels to the upper or lower end of the steam-cylinder E, thus by themovement of the stem up and down opening and closing the reversing valve K.

Fig. 2 is an enlarged view of said stem, its upper end being split lengthwise to the depth of its play in the cap and a spring inserted, which, when the stem is placed in the cap, will be compressed and give the desired friction between the sides of the upper end ofthe stem and the inside of the cap, all ot' which will be readily understood by those skilled in the art.

The sections of the split end ot' the valvestem are held together and tothespring by screws or studs, the heads of which are countersunk within the smaller section.

1. A reversing-valve stem an end of which is provided with an expansible and compressibleindependent section, substantially as speciiied.

2. A reversing-valve stem an end portion of which is split or constructe-din two sections, combined'with a spring interposed between said sections, substantiallyas and for the purpose specied.

3. As an improvementinpower-brake mechanism, a reversing-valve stem an end of which is provided with an expansible and compressible section, combined with its guide orI cap, whereby the necessary frictional contact is produced between the stem and its guide or cap without the intervention ot' packing, substantially as specified.

In testimony whereof Ihave hereunto subscribed my name this 22d day of March,-vA. 

